February 27, 2008
People with early Alzheimer's disease had more car accidents and performed more poorly on road tests than their mentally sharp peers. Those are the findings of a new study from researchers at Rhode Island Hospital and Brown University.
The study, published in the medical journal Neurology, found that while driving skills declined during the early phases of Alzheimer's disease, some people with very mild dementia can continue to drive safety for extended periods of time. The study included 128 individuals 84 with early Alzheimer's and 44 age-matched control subjects without cognitive impairments.
Drivers with early Alzheimer's were followed every six months over two to three years. The study assessed driving abilities through self-reports, reports from family members, and a standardized road test.
"The findings indicate that people with very mild dementia may be able to drive safely for longer periods of time," Dr. Ott noted. "It is clear, however, that driving ability declines fairly rapidly among patients with dementia, and therefore, regular follow-up assessments are warranted in these people with very mild dementia."
Currently, the American Academy of Neurology Guideline on Risk of Driving and Alzheimer's Disease recommends a reassessment every six months for people diagnosed with very mild dementia who continue to drive.
The study also found that increased age as well as lower education can impact driving abilities. The odds of failing a road test increased by about 6 percent for every year exceeding the age of 75, the study found. In addition, drivers with less education within the study group were more likely to fail a road test. Failure was 10 percent more likely for each year of education less than the group's average.
Overall, Dr. Ott said, "The results suggest that a regular driving assessment program may actually reduce the frequency of motor vehicle accidents in drivers with mild dementia by increasing awareness among the driver and caregivers. This, however, may also result in premature termination of driving privileges for some persons with dementia."
The researchers note that doctors face a major challenge in developing valid and reliable office screening tools to assess driving. Such tests can assist the clinician with making driving assessment recommendations regarding driving safety for those with early Alzheimer's.
Driving safely is an issue for any older driver. Per mile driven, the accident rate is nine times higher for those 85 and older, compared to younger drivers aged 25 to 69. If someone has failing cognition due to early Alzheimer's or other forms of mental decline, the likelihood of a car crash is much greater.
Yet imposing driving restrictions can be hard for anyone to accept. Driving affords older people a coveted sense of independence and connection to the wider community at large. Taking away a license can be devastating to self-esteem and make life more difficult for seniors and family members both.
Alzheimer's disease is of particular concern, because patients may be unaware of their progressive mental decline and the threats they pose on the road. Unlike someone who has a condition such as failing eyesight or arthritis, for example, who often cuts down on his or her own driving voluntarily, a patient with Alzheimer's may stay behind the wheel longer and drastically misjudge their ability to continue driving.
In the case of Alzheimer's, it often falls on caregivers to assess the driver and enforce a driving ban. It is particularly important that family members look for any signs of mental decline in loved ones and discuss concerns with a physician.
Family members and doctors also need to counsel the patient to prepare him or her for stopping driving and get them to accept a "no driving" status. In this way, caregivers and people with Alzheimer's can help to assure safety for loved ones and strangers alike.
Ott, B. Neurology, Jan. 23, 2008; advance online edition.
Alzheimer's Association: "Driving."
News release, Rhode Island Hospital